Acrylic-halogenated polyolefin copolymer adhesion promoters

ABSTRACT

The present invention is directed to a method for producing a copolymer and a copolymer product of the method. The copolymer is prepared by a controlled radical polymerization process, typically an atom transfer radical polymerization process, in which polymerizable alkene monomers are polymerized in the presence of a halogenated polyolefin macroinitiator. The copolymer product of this process is useful in a film-forming composition that adheres strongly to polyolefinic substrates and to which non-polyolefinic film-forming compositions strongly adhere. The copolymer can be applied to a substrate in an adhesion-promoting layer or can be incorporated into a film-forming composition, such as a primer, that contains additional resinous compounds.

FIELD OF THE INVENTION

[0001] The present invention relates to adhesion promoters that improveadhesion between film-forming coatings and adhesives and polyolefinicsubstrates. The adhesion promoters are prepared by controlled radicalpolymerization using a halogenated polyolefin as a macroinitiator.

BACKGROUND OF THE INVENTION

[0002] Polyolefins, such as polypropylene and polyethylene are used in awide variety of molding applications including, for example, inpreparation of molded parts for use in the automotive, industrial andappliance markets. The preparation of such molded articles generallyincludes the steps of molding an article from the polyolefin resin andapplying to the molded article one or more film-forming coating layersto protect and/or color the article and/or an adhesive to attach themolded article to another article.

[0003] One difficulty with use of poyolefinic substrates is that typicalfilm-forming coatings and adhesives do not adhere well to the substrate.In the case of a film-forming coating applied to the substrate, thelayer delaminates. In the case of adhesives, adhesive failure iscommonplace.

[0004] A solution to the failure of coatings and adhesives to adhere tothe polyolefinic substrate is to include a layer of a film-formingcomposition including a chlorinated polyolefin (CPO) between thesubstrate and the film-forming coating or adhesive. This adds aprocessing step and, since chlorinated polyolefins are relativelyexpensive, adding to the cost of using polyolefins to produce moldedparts.

[0005] U.S. Pat. No. 5,955,545 discloses use of CPO-acrylic graftcopolymers as adhesion promoters that assertedly improve adhesion ofsubsequent coating layers and/or adhesives to polyolefins. However,these graft copolymer adhesion promoters are prepared by standard freeradical polymerization methods and suffer from high polydispersity andthe presence of non-graft polymer chains and acrylic copolymers andhomopolymers in the resin composition as a result of the random natureof standard radical polymerization processes. The high polydispersityand additional non-graft chains present in the same mixture as the graftpolymer results in incomplete or inefficient adhesion promotion andinterference with the curing dynamics of the resin. Further, thesecompositions are unstable, readily falling out of solution, especiallywhen incorporated in a film-forming composition, and they absorb andscatter light, giving a hazy appearance. Thus, they are unsuitable formany coating applications.

[0006] It is, therefore, desirable to have well defined adhesionpromoting material that includes polyolefinic segments or portions thatinteract strongly with polyolefinic substrates as well as portions ornon-polyolefinic segments that interact well with film-forming resins,crosslinkers and/or curing agents and solvents that are present in atypical coating composition. It is also desirable that the adhesionpromoter be of a more defined architecture than is typically found ingraft copolymers formed by a free radical process. The definedarchitecture will allow for design of copolymers that interact withother components of the coating composition in a consistent manner withless contamination with undesirable polymer species that typicallyresult from free radical grafting to CPOs. The low polydispersity of thematerial, combined with the substantial absence of undesirable polymerspecies would yield a clear, stable coating additive or coatingcomposition that would adhere well to polyolefinic substrates.

[0007] A wide variety of radically polymerizable monomers, such asmethacrylate and acrylate monomers, are commercially available and canprovide a wide range of properties including, for example, hydrophilicand hydrophobic properties, the ability to interact with crosslinkers,or to self crosslink.

[0008] U.S. Pat. Nos. 5,807,937; 5,789,487; and 5,763,548 andInternational Patent Publication Nos. WO 98/40415; WO 98/01480; WO97/18247; and WO 96/30421 describe a radical polymerization processreferred to as atom transfer radical polymerization (ATRP). The ATRPprocess is described as being a living radical polymerization thatresults in the formation of (co)polymers having predictable molecularweight and molecular weight distribution. The ATRP process is alsodescribed as providing highly uniform products having controlledstructure (i.e., controllable topology, composition, etc.). The '937 and'548 patents also describe (co)polymers prepared by ATRP, which areuseful in a wide variety of applications including, for example,dispersants and surfactants.

[0009] U.S. Pat. Nos. 5,478,886; 5,272,201; 5,221,334; 5,219,945;5,085,698; 4,812,517; and 4,755,563 describe ABC, AB and BAB blockcopolymers and pigmented ink compositions containing such blockcopolymers. The block copolymers of the '886, '201, '334, '945, '698,'517 and '563 patents are described as being prepared by living orstepwise polymerization processes, such as anionic or group transferpolymerization.

[0010] A number of initiators and macroinitiators are known to supportATRP polymerization. These initiators are described, for example, inU.S. Pat. Nos. 5,807,937 and 5,986,015. U.S. Pat. No. 5,807,937discloses a number of initiators, including a macroinitiator, wherehalide groups attached to an activated benzylic carbon serve as theinitiating site. The '937 patent discloses that benzyl halides can beefficient initiators for ATRP in monomeric form as well as in a polymer.

[0011] WO 9840415 A1 discloses ATRP macroinitiators having an activatedhalogen, which have been prepared by chlorosulfonation of polyethylene.The chlorosulfonyl group is known to be a good ATRP initiator inmonomeric form.

[0012] Paik et al. (“Synthesis and Characterization of Graft Copolymersof Poly(vinyl chloride) with Styrene and (Meth) acrylates by AtomTransfer Polymerization”, Macromol. Rapid Commun., 19, 47-52(1998))disclose that polyvinyl chloride is incapable of serving as an initiatorin an ATRP process. Paik further discloses that ATRP can be initiated bythe activated chlorine in a chloroacetate group attached to a PVCbackbone. Paik also discloses that the secondary chlorines on the PVCbackbone do not initiate ATRP. Collectively, the prior art indicatesthat effective ATRP macroinitiators should contain activated halogens.

SUMMARY OF THE INVENTION

[0013] In accordance with the present invention, an alkenyl (co)polymeris provided that is prepared by polymerizing alkenyl monomers in thepresence of an initiator or macroinitiator (collectively “an initiator”)having halide groups attached to tertiary carbons under atom transferradical polymerization conditions. An example of such an initiator is,without-limitation, a halogenated polyolefin such as a chlorinated orbrominated polypropylene, polybutylene or branched polyethylene. Thispolymer finds use in a variety of applications, such as, withoutlimitation, in compositions for coating, molding and extruding. Atypical use for the copolymer is as an additive to a film-forming resincomposition for coating a polyolefinic substrate. The additive bothpromotes interlayer adhesion between the coating composition layer andthe polyolefinic substrate and can be crosslinked into the film-formingresin.

[0014] A curable film-forming composition including thealkenyl-halogenated polyolefin copolymer is also provided. The halogencontent of the halogenated polyolefin embodiment is typically eitherchlorine or bromine. The number of halide groups in the initiator canvary, but typically falls between about 15% to 45% by weight of theinitiator, as is commonly found in commercially available halogenatedpolyolefins.

[0015] A method of coating a polyolefinic substrate also is providedthat includes applying to the polyolefinic substrate a film-formingcomposition comprising the above-described vinyl-halogenated polyolefincopolymer. A coated article prepared according to the method is alsodescribed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Other than in the operating examples, or where otherwiseindicated, all numbers or expressions referring to quantities ofingredients, reaction conditions, etc, used in the specification andclaims are to be understood as modified in all instances by the term“about”. As used herein, the term “polymer”, and the like, is intendedto include both polymers and oligomers unless stated otherwise. The term“copolymer” is intended to include both random or block copolymersunless specified otherwise.

[0017] As described above, the present invention is a polymericcomposition prepared by an ATRP process. The process utilizes a novelATRP initiator that expands the type of copolymers that can be preparedby the ATRP process and the uses therefor. The initiator is ahalogenated polyolefin, resulting in the production of a graft copolymeruseful as an additive in a coating composition for polyolefinicsubstrates, among other uses. By the term “polyolefinic substrate” it ismeant as a substrate having, on at least a portion of its surface, apolyolefinic composition.

[0018] The copolymer of the present invention is prepared by controlledradical polymerization. As used herein and in the claims, the term“controlled radical polymerization”, and related terms, e.g., “livingradical polymerization”, refer to those methods of radicalpolymerization that provide control over the molecular weight, polymerchain architecture and polydispersity of the resulting polymer. Acontrolled or living radical polymerization is also described as achain-growth polymerization that propagates with essentially no chaintransfer and essentially no chain termination. The number of livingpolymer chains formed during a controlled radical polymerization isoften nearly equal to the number of initiators present at the beginningof the reaction. Each living polymer chain typically contains a residueof the initiator at what is commonly referred to as its tail and aresidue of the radically transferable group at what is commonly referredto as its head.

[0019] In an embodiment of the present invention, the copolymer isprepared by atom transfer radical polymerization (ATRP). The typicalATRP process can be described generally as including the steps ofpolymerizing one or more radically polymerizable monomers in thepresence of an initiation system; forming a polymer; and isolating theformed polymer. In the present invention, the initiation systemcomprises a halogenated polyolefinic initiator; a transition metalcompound, i.e., a catalyst, which participates in a reversible redoxcycle with the initiator; and a ligand, which coordinates with thetransition metal compound. The ATRP process is described in furtherdetail in International Patent Publication WO 98/40415 and U.S. Pat.Nos. 5,807,937; 5,763,548 and 5,789,487.

[0020] In the present invention, ATRP is performed using a polymer whichhas not been modified to introduce a known activated halogen group orhas it been modified as the result of copolymerization of a monomercontaining a known activated halogen group. Thus, in the presentinvention, an unmodified halogen containing polymer is the site for ATRPinitiation. Post polymerization modification or inclusion of a specialATRP initiating monomer are not required. This avoids additional processsteps in the first case and avoids making a special copolymer in thesecond.

[0021] There are a number of potential explanations as to the exactchemical reason for ATRP functioning well in an unmodified halogencontaining polymer, without the presence of the prior art activatedhalogens. Without wishing to be bound to any single theory, it isbelieved that the inductive effect of other halogens on the main polymerchain in proximity to the initiating halogen is responsible for itsability to initiate ATRP. Given the free radical nature of ATRP, it isbelieved that the tertiary halogens on the polymer are the most prone toact as ATRP initiation sites.

[0022] Catalysts that may be used in the ATRP preparation of thecopolymer of the present invention include any transition metal compoundthat can participate in a redox cycle with the initiator and the growingpolymer chain. It is preferred that the transition metal compound notform direct carbon-metal bonds with the polymer chain. Transition metalcatalysts useful in the present invention may be represented by thefollowing general formula (I),

TM^(n+)X_(n)  (I)

[0023] wherein TM is the transition metal, n is the formal charge on thetransition metal having a value of from 0 to 7, and X is a counterion ora covalently bonded component. Examples of the transition metal (TM)include, but are not limited to, copper, iron, gold, silver, mercury,palladium, platinum, cobalt, manganese, ruthenium, molybdenum, niobiumand zinc. Examples of X include, but are not limited to, halide,hydroxy, oxygen, C₁-C₆-alkoxy, cyano, cyanato, thiocyanato and azido. Apreferred transition metal is Cu(I) and X is preferably halide, e.g.,chloride. Accordingly, a preferred class of transition metal catalystsare the copper halides, e.g., Cu(I)Cl. It is also preferred that thetransition metal catalyst contain a small amount, e.g., one molepercent, of a redox conjugate, for example, Cu(II)Cl₂ when Cu(I)Cl isused. Additional catalysts useful in preparing the polymer are describedin U.S. Pat. No. 5,807,937 at column 18, lines 29 through 56. Redoxconjugates are described in further detail in U.S. Pat. No. 5,807,937 atcolumn 11, line 1 through column 13, line 38.

[0024] Ligands that may be used in the ATRP preparation of the copolymerinclude, but are not limited to, compounds having one or more carbon,nitrogen, oxygen, phosphorus and/or sulfur atoms, which can coordinateto the transition metal catalyst compound, e.g., through sigma and/or pibonds. Classes of useful ligands include, but are not limited to,unsubstituted and substituted pyridines and bipyridines; porphyrins;cryptands; crown ethers, e.g., 18-crown-6; polyamines, e.g.,ethylenediamine; glycols, e.g., alkylene glycols, such as ethyleneglycol and carbon monoxide. As used herein and in the claims, the term“(meth)acrylate” and similar terms refer to acrylates, methacrylates,and mixtures of acrylates and methacrylates. A preferred class ofligands are the substituted bipyridines, e.g., 4,4′-dialkyl-bipyridyls.Additional ligands that may be used in preparing the polymer aredescribed in U.S. Pat. No. 5,807,937 at column 18, line 57 throughcolumn 21, line 43.

[0025] The present invention utilizes novel macroinitiators that aretypically halogenated polyolefins. The initiator includes one or moreATRP initiation sites that is a halide group attached to a tertiarycarbon (hereinafter “tertiary halide”). A halide group that is capableof serving as an ATRP initiation site, whether or not a tertiary,secondary or primary halide, or otherwise, is hereinafter referred to asa “dormant halide”, as opposed to a halide that is not capable ofserving efficiently as a site of ATRP initiation.

[0026] Suitable macroinitiators include, without limitation, halogenatedpolyolefins such as polypropylene and polybutylene. The halide group istypically chlorine and/or bromine. The macroinitiator also can be abranched polyethylene containing a suitable number of tertiary halides.

[0027] As used herein and in the claims, by “olefin” and like terms itis meant unsaturated aliphatic hydrocarbons having one or more doublebonds, such as obtained by cracking petroleum fractions. Specificexamples of olefins include, but are not limited to, propylene,1-butene, 1,3-butadiene, isobutylene and diisobutylene. A “polyolefin”is a polymer formed from olefins. Common examples are polypropylene andpolybutylene and include the class of thermoplastic polyolefins (TPOs).The polyolefin may be homopolymeric or copolymeric. A variety ofhomopolymeric halogenated polyolefins are available from EastmanChemical Company, among others. A halogenated polyolefin is ahalogen-substituted polyolefin, and is typically chlorinated orbrominated.

[0028] There is no literal limit as to the density of halides on thepolyolefin backbone of the initiator. However, the halogenatedpolyolefin typically is a chlorinated or brominated polyolefin having15% to 45% by weight halide groups, with at least about 80% of thehalides being attached to tertiary carbons and, therefore, being dormanthalides. Halogenated polyolefins having 15% to 45% by weight halidegroups represent most commercially available halogenated polyolefins.However, when halogenated polyolefins having 15% to 45% by weight,halide groups are used as ATRP initiators, the resultant ATRP-producedcopolymers are preferred as adhesion promoters for coating compositionsused to coat polyolefinic substrates. Having a higher density of halidegroups on the polyolefinic backbone of the initiator typically resultsin insufficient adhesion of copolymer-containing coating to thepolyolefinic substrate. Too little halogenation of the polyolefinicbackbone of the macroinitiator may result in poor compatibility of thecopolymer with the coating composition in which it is dispersed and lackof other desirable functionality in the copolymer, such as sufficientcrosslinking density. The most preferred halide group density on thepolyolefin initiator will depend upon the ultimate end use for theATRP-produced copolymer and, therefore, will vary from use-to-use.

[0029] Monomers that may be polymerized by the ATRP process of thepresent invention include all alpha, beta ethylenically unsaturatedmonomers that are known to be capable of polymerization by the ATRPprocess. Any radically polymerizable alkene containing a polar group canserve as a monomer for polymerization. The preferred monomers includethose of the formula (II):

[0030] wherein R₄ and R₅ are independently selected from the groupconsisting of H, halogen, CN, CF₃, straight or branched alkyl of 1 to 20carbon atoms (preferably from 1 to 6 carbon atoms, more preferably from1 to 4 carbon atoms), aryl, α,β-unsaturated straight or branched alkenylor alkynyl of 2 to 10 carbon atoms (preferably from 2 to 6 carbon atoms,more preferably from 2 to 4 carbon atoms), α,β-unsaturated straight orbranched alkenyl of 2 to 6 carbon atoms (preferably vinyl) substituted(preferably at the α-position) with a halogen (preferably chlorine),C₃-C₈ cycloalkyl, heterocyclyl, phenyl which may optionally have from1-5 substituents on the phenyl ring, C(═Y)R₈, C(═Y)NR₉R₁₀, YCR₉R₁₀R₁₁and YC(═Y)R₁₁, where Y may be NR₁₁ or 0 (preferably 0), R₈ is alkyl offrom 1 to 20 carbon atoms, alkoxy of from 1 to 20 carbon atoms, aryloxyor heterocyclyloxy, R₉ and R₁₀ are independently H or alkyl of from 1 to20 carbon atoms, or R₉ and R₁₀ may be joined together to form analkylene group of from 2 to 5 carbon atoms, thus forming a 3- to6-membered ring, and R₁₁ is H, straight or branched C₁-C₂₀, alkyl andaryl; and

[0031] R₆ is selected from the group consisting of H, halogen(preferably fluorine or chlorine), C₁-C₆ (preferably C₁)alkyl, CN,COOR₁₂ (where R₁₂ is H, an alkali metal, or a C₁-C₆ alkyl group) oraryl; or

[0032] R₄ and R₆ may be joined to form a group of the formula (CH₂)_(n),(which may be substituted with from 1 to 2n′ halogen atoms or C₁-C₄alkyl groups) or C(═O)—Y—C(═O), where n′ is from 2 to 6 (preferably 3 or4) and Y is as defined above; or

[0033] R₇ is the same as R₄ or R₅ or optionally R₇ is a CN group; atleast two of R₄, R₅, and R₆ are H or halogen.

[0034] In the context of the present application, the terms “alkyl”,“alkenyl” and “alkynyl” refer to straight-chain or branched groups.

[0035] Furthermore, in the present application, “aryl” refers to phenyl,naphthyl, phenanthryl, phenalenyl, anthracenyl, triphenylenyl,fluoranthenyl, pyrenyl, pentacenyl, chrysenyl, naphthacenyl, hexaphenyl,picenyl and perylenyl (preferably phenyl and naphthyl), in which eachhydrogen atom may be replaced with alkyl of from 1 to 20 carbon atoms(preferably from 1 to 6 carbon atoms and, more preferably, methyl),alkyl of from 1 to 20 carbon atoms (preferably from 1 to 6 carbon atomsand, more preferably, methyl) in which each of the hydrogen atoms isindependently replaced by a halide (preferably a fluoride or achloride), alkenyl of from 2 to 20 carbon atoms, alkynyl of from 1 to 20carbon atoms, alkoxy of from 1 to 6 carbon atoms, alkylthio of from 1 to6 carbon atoms, C₃-C₈ cycloalkyl, phenyl, halogen, NH₂,C₁-C₆-alkylamino, C₁-C₆-dialkylamino, and phenyl which may besubstituted with from 1 to 5 halogen atoms and/or C₁-C₄ alkyl groups.(This definition of “aryl” also applies to the aryl groups in “aryloxy”and “aralkyl”.) Thus, phenyl may be substituted from 1 to 5 times andnaphthyl may be substituted from 1 to 7 times (preferably, any arylgroup, if substituted, is substituted from 1 to 3 times) with one of theabove substituents. More preferably, “aryl” refers to phenyl, naphthyl,phenyl substituted from 1 to 5 times with fluorine or chlorine, andphenyl substituted from 1 to 3 times with a substituent selected fromthe group consisting of alkyl of from 1 to 6 carbon atoms, alkoxy offrom 1 to 4 carbon atoms and phenyl. Most preferably, “aryl”, refers tophenyl and tolyl.

[0036] In the context of the present invention, “heterocyclyl” refers topyridyl, furyl, pyrrolyl, thienyl, imidazolyl, pyrazolyl, pyrazinyl,pyrimidinyl, pyridazinyl, pyranyl, indolyl, isoindolyl, indazolyl,benzofuryl, isobenzofuryl, benzothienyl, isobenzothienyl, chromenyl,xanthenyl, purinyl, pteridinyl, quinolyl, isoquinolyl, phthalazinyl,quinazolinyl, quinoxalinyl, naphthyridinyl, phenoxathiinyl, carbazolyl,cinnolinyl, phenanthridinyl, acridinyl, 1,10-phenanthrolinyl,phenazinyl, phenoxazinyl, phenothiazinyl, oxazolyl, thiazolyl,isoxazolyl, isothiazolyl, and hydrogenated forms thereof known to thosein the art. Preferred heterocyclyl groups include pyridyl, furyl,pyrrolyl, thienyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl,pyridazinyl, pyranyl and indolyl, the most preferred heterocyclyl groupbeing pyridyl. Accordingly, suitable vinyl heterocyclyls to be used as amonomer in the present invention include 2-vinyl pyridine, 4-vinylpyridine, 2-vinyl pyrrole, 3-vinyl pyrrole, 2-vinyl oxazole, 4-vinyloxazole, 5-vinyl oxazole, 2-vinyl thiazole, 4-vinyl thiazole, 5-vinylthiazole, 2-vinyl imidazole, 4-vinyl imidazole, 3-vinyl pyrazole,4-vinyl pyrazole, 3-vinyl pyridazine, 4-vinyl pyridazine, 3-vinylisoxazole, 3-vinyl isothiazoles, 2-vinyl pyrimidine, 4-vinyl pyrimidine,5-vinyl pyrimidine, and any vinyl pyrazine, the most preferred being2-vinyl pyridine. The vinyl heterocyclyls mentioned above may bear oneor more (preferably 1 or 2) C₁-C₆ alkyl or alkoxy groups, cyano groups,ester groups or halogen atoms, either on the vinyl group or theheterocyclyl group, but preferably on the heterocyclyl group. Further,those vinyl heterocyclyls which, when unsubstituted, contain an N—Hgroup may be protected at that position with a conventional blocking orprotecting group, such as a C₁-C₆ alkyl group, a tris-C₁-C₆ alkylsilylgroup, an acyl group of the formula R₁₃CO (where R₁₃ is alkyl of from 1to 20 carbon atoms, in which each of the hydrogen atoms may beindependently replaced by halide, preferably fluoride or chloride),alkenyl of from 2 to 20 carbon atoms (preferably vinyl), alkynyl of from2 to 10 carbon atoms (preferably acetylenyl), phenyl which may besubstituted with from 1 to 5 halogen atoms or alkyl groups of from 1 to4 carbon atoms, or aralkyl (aryl-substituted alkyl, in which the arylgroup is phenyl or substituted phenyl and the alkyl group is from 1 to 6carbon atoms), etc. (This definition of “heterocyclyl” also applies tothe heterocyclyl groups in “heterocyclyloxy” and “heterocyclic ring”.)More specifically, preferred monomers include (but are not limited to)styrene, p-chloromethylstyrene, vinyl chloroacetate, acrylate andmethacrylate esters of C₁-C₂₀ alcohols, isobutene,2-(2-bromopropionoxy)ethyl acrylate, acrylonitrile, andmethacrylonitrile.

[0037] The monomer containing at least one polar group may be present inan amount of 5 to 100 wt % by weight based on the total amount ofmonomers. A preferred amount of the monomer containing at least onepolar group is 10 to 100 wt %; the most preferred amount is 20 to 100 wt% based on the total amount of monomers. This is particularly importantin the case of acrylonitrile because an amount of at least 20 wt %assures solvent resistance properties of the resulting polymer A.

[0038] Examples of suitable monomers may each be independently selectedfrom vinyl monomers, allylic monomers, olefins, (meth)acrylic acid,(meth)acrylates, (meth)acrylamide, N- and N,N-disubstituted(meth)acrylamides, vinyl aromatic monomers, vinyl halides, vinyl estersof carboxylic acids and mixtures thereof. More specific examples ofsuitable monomers include, without limitation, C₁-C₂₀alkyl(meth)acrylates (including linear or branched alkyls andcycloalkyls) which include, but are not limited to,methyl(meth)acrylate, ethyl (meth)acrylate, propyl(meth)acrylate,isopropyl (meth)acrylate, n-butyl(meth)acrylate, iso-butyl(meth)acrylate, tert-butyl(meth)acrylate, 2-ethylhexyl (meth)acrylate,lauryl(meth)acrylate, isobornyl (meth)acrylate,cyclohexyl(meth)acrylate, 3,3,5-trimethylcyclohexyl(meth)acrylate andisocane(meth)acrylate; (meth)acrylate esters of C₁-C₂₀ alcohols; oxiranefunctional (meth)acrylates which include, but are not limited to,glycidyl(meth)acrylate, 3,4-epoxycyclohexylmethyl(meth)acrylate, and2-(3,4-epoxycyclohexyl)ethyl(meth)acrylate; hydroxy alkyl(meth)acrylates having from 2 to 4 carbon atoms in the alkyl group whichinclude, but are not limited to, hydroxyethyl (meth)acrylate,hydroxypropyl(meth)acrylate and hydroxybutyl (meth)acrylate. Theresidues may each independently be residues of monomers having more thanone (meth)acryloyl group, such as (meth)acrylic anhydride,diethyleneglycol bis(meth)acrylate, 4,4′-isopropylidenediphenolbis(meth)acrylate (Bisphenol A di(meth)acrylate), alkoxylated4,4′-isopropylidenediphenol bis(meth)acrylate, trimethylolpropanetris(meth)acrylate and alkoxylated trimethylolpropanetris(meth)acrylate.

[0039] Specific examples of vinyl aromatic monomers that may be used toprepare the polymer include, but are not limited to, styrene,p-chloromethyl styrene, divinyl benzene, vinyl naphthalene and divinylnaphthalene. Vinyl halides that may be used to prepare the graftcopolymer include, but are not limited to, vinyl chloride and vinylidenefluoride. Vinyl esters of carboxylic acids that may be used to preparethe graft copolymer include, but are not limited to, vinyl acetate,vinyl butyrate, vinyl 3,4-dimethoxybenzoate and vinyl benzoate.

[0040] As used herein and in the claims, by the term “allylicmonomer(s)” it is meant monomers containing substituted and/orunsubstituted allylic functionality, i.e., one or more radicalsrepresented by the following general formula III,

H₂C═C(R₁)—CH₂—  (III)

[0041] wherein R₁ is hydrogen, halogen or a C₁ to C₄ alkyl group. Mostcommonly, R₁ is hydrogen or methyl and consequently general formula IIIrepresents the unsubstituted (meth)allyl radical. Examples of allylicmonomers may each independently be residues that include, but are notlimited to, (meth)allyl ethers, such as methyl(meth)allyl ether and(meth)allyl glycidyl ether; allyl esters of carboxylic acids, such as(meth)allyl acetate, (meth)allyl butyrate, (meth)allyl3,4-dimethoxybenzoate and (meth)allyl benzoate.

[0042] Other ethylenically unsaturated radically polymerizable monomersthat may be used to prepare the copolymer include, but are not limitedto, cyclic anhydrides, e.g., maleic anhydride,1-cyclopentene-1,2-dicarboxylic anhydride and itaconic anhydride; estersof acids that are unsaturated but do not have α,β-ethylenicunsaturation, e.g., methyl ester of undecylenic acid; diesters ofethylenically unsaturated dibasic acids, e.g., di(C₁-C₄ alkyl)ethylmaleates; maleimide and N-substituted maleimides.

[0043] In an embodiment of the present invention, the monomer includes ahydrophobic residue of a monomer selected from oxirane functionalmonomer reacted with a carboxylic acid selected from the groupconsisting of aromatic carboxylic acids, polycyclic aromatic carboxylicacids, aliphatic carboxylic acids having from 6 to 20 carbon atoms andmixtures thereof; C₆-C₂₀ alkyl(meth)acrylates, e.g., including those aspreviously recited herein; aromatic (meth)acrylates, e.g.,phenyl(meth)acrylate, p-nitrophenyl(meth)acrylate and benzyl(meth)acrylate; polycyclicaromatic (meth)acrylates, e.g.,2-naphthyl(meth)acrylate; vinyl esters of carboxylic acids, e.g.,hexanoic acid vinyl ester and decanoic acid vinyl ester; N,N-di(C₁-C₈alkyl) (meth)acrylamides; maleimide; N-(C₁-C₂₀ alkyl) maleimides;N-(C₃-C₈ cycloalkyl) maleimides; N-(aryl) maleimides; and mixturesthereof. Examples of N-substituted maleimides include, but are notlimited to, N-(C₁-C₂₀ linear or branched alkyl) maleimides, e.g.,N-methyl maleimide, N-tertiary-butyl maleimide, N-octyl maleimide andN-icosane maleimide; N-(C₃-C₈ cycloalkyl) maleimides, e.g., N-cyclohexylmaleimide; and N-(aryl) maleimides, e.g., N-phenyl maleimide, N-(C₁-C₉linear or branched alkyl substituted phenyl) maleimide, N-benzylmaleimide and N-(C₁-C₉ linear or branched alkyl substituted benzyl)maleimide.

[0044] The oxirane functional monomer or its residue that is reactedwith a carboxylic acid, may be selected from, for example,glycidyl(meth)acrylate, 3,4-epoxycyclohexylmethyl(meth)acrylate,2-(3,4-epoxycyclohexyl) ethyl(meth)acrylate, allyl glycidyl ether andmixtures thereof. Examples of carboxylic acids that may be reacted withthe oxirane functional monomer or its residue include, but are notlimited to, para-nitrobenzoic acid, hexanoic acid, 2-ethyl hexanoicacid, decanoic acid, undecanoic acid and mixtures thereof.

[0045] Other useful monomers include vinyl chloroacetate, isobutene,2-(2-bromopropionoxy)ethyl acrylate and (meth)acrylonitrile.

[0046] In the ATRP preparation of the copolymer, the amounts andrelative proportions of the initiator, the transition metal compound andthe ligand are those for which ATRP is most effectively performed. Theamount of initiator used can vary widely and is typically present in thereaction medium in a concentration of from 10⁻⁴ moles/liter (M) to 3M,for example, from 10⁻³M to 10⁻¹M. As the molecular weight of thecopolymer product can be directly related to the relative concentrationsof initiator and monomer(s), the molar ratio of initiator to monomer isan important factor in copolymer preparation. The molar ratio ofinitiator to monomer is typically within the range of 10⁻⁴:1 to 0.5:1,for example, 10⁻³:1 to 5×10⁻²:1.

[0047] In preparing the copolymer by ATRP methods, the molar ratio oftransition metal compound to initiator is typically in the range of10⁻⁴:1 to 10:1, for example, 0.1:1 to 5:1. The molar ratio of ligand totransition metal compound is typically within the range of 0.1:1 to100:1, for example, 0.2:1 to 10:1.

[0048] The copolymer may be prepared in the absence of solvent, i.e., bymeans of a bulk polymerization process. Generally, the copolymer isprepared in the presence of a solvent, typically water and/or an organicsolvent. Classes of useful organic solvents include, but are not limitedto, esters of carboxylic acids, ethers, cyclic ethers, C₅-C₁₀ alkanes,C₅-C₈ cycloalkanes, aromatic hydrocarbon solvents, halogenatedhydrocarbon solvents, amides, nitrites, sulfoxides, sulfones andmixtures thereof. Supercritical solvents, such as CO₂, C₁-C₄ alkanes andfluorocarbons, may also be employed. A preferred class of solvents arethe aromatic hydrocarbon solvents, particularly preferred examples ofwhich are xylene, toluene and mixed aromatic solvents such as thosecommercially available from Exxon Chemical-America under the trademarkSOLVESSO. Additional solvents are described in further detail in U.S.Pat. No. 5,807,937 at column 21, line 44 through column 22, line 54.

[0049] The ATRP preparation of the copolymer is typically conducted at areaction temperature within the range of 25° C. to 140° C., e.g., from50° C. to 100° C., and a pressure within the range of 1 to 100atmospheres, usually at ambient pressure. The ATRP is typicallycompleted in less than 24 hours, e.g., between 1 and 8 hours.

[0050] The ATRP transition metal catalyst and its associated ligand aretypically separated or removed from the copolymer product prior to itsuse, for instance, as an adhesion-promoting additive. Removal of theATRP catalyst may be achieved using known methods, including, forexample, adding a catalyst binding agent to the mixture of thecopolymer, solvent and catalyst, followed by filtering. Examples ofsuitable catalyst binding agents include, for example, alumina, silica,clay or a combination thereof. A mixture of the copolymer, solvent andATRP catalyst may be passed through a bed of catalyst binding agents.Alternatively, the ATRP catalyst may be oxidized in situ, the oxidizedresidue of the catalyst being retained in the polymer.

[0051] The copolymer can be a block copolymer having one or moresegments. In a two-segment copolymer, the copolymer may have the generalformula IV:

φ-(A_(p)-B_(s)—X)_(t)  (IV)

[0052] where each of A and B in general formula IV may represent one ormore types of monomer residues, while p and s represent the averagetotal number of A and B residues occurring per block or segment of Aresidues (A-block or A-segment) and B residues (B-block or B-segment),respectively, and t refers to the number of initiator sites present onthe initiator, φ. When containing more than one type or species ofmonomer residue, the A- and B-blocks may each have at least one ofrandom block, e.g., di-block and tri-block, alternating and gradientarchitectures. Gradient architecture refers to a sequence of differentmonomer residues that change gradually in a systematic and predictablemanner along the polymer backbone. For purposes of illustration, anA-block containing 6 residues of methyl methacrylate (MMA) and 6residues of ethyl methacrylate (EMA), for which p is 12, may havedi-block, tetra-block, alternating and gradient architectures asrepresented in general formulas V, VI, VII and VIII.

V Di-Block Architecture

[0053] -(MMA-MMA-MMA-MMA-MMA-MMA-EMA-EMA-EMA-EMA-EMA-EMA)-

VI Tetra-Block Architecture

[0054] -(MMA-MMA-MMA-EMA-EMA-EMA-MMA-MMA-MMA-EMA-EMA-EMA)-

VII Alternating Architecture

[0055] -(MMA-EMA-MMA-EMA-MMA-EMA-MMA-EMA-MMA-EMA-MMA-EMA)-

VIII Gradient Architecture

[0056] -(MMA-MMA-MMA-EMA-MMA-MMA-EMA-EMA-MMA-EMA-EMA-EMA)-

[0057] The B-block may be described in a manner similar to that of theA-block.

[0058] The order in which monomer residues occur along the polymerbackbone of the copolymer is typically determined by the order in whichthe corresponding monomers are fed into the vessel in which thecontrolled radical polymerization is conducted. For example, inreference to general formula IV, the monomers that are incorporated asresidues in the A-block of the copolymer are generally fed into thereaction vessel prior to those monomers that are incorporated asresidues in the B-block.

[0059] During formation of the A- and B-blocks, if more than one monomeris fed into the reaction vessel at a time, the relative reactivities ofthe monomers typically determine the order in which they areincorporated into the living polymer chain. Gradient sequences ofmonomer residues within the A- and B-blocks can be prepared bycontrolled radical polymerization, and in particular by ATRP methods by(a) varying the ratio of monomers fed to the reaction medium during thecourse of the polymerization, (b) using a monomer feed containingmonomers having different rates of polymerization, or (c) a combinationof (a) and (b). Copolymers containing gradient architecture aredescribed in further detail in U.S. Pat. No. 5,807,937 at column 29,line 29 through column 31, line 35.

[0060] Subscripts p and s represent average numbers of residuesoccurring in the respective A- and B-blocks. Typically, subscript s hasa value of at least 1, and preferably at least 5 for general formula IV.Also, subscript s has a value of typically less than 300, preferablyless than 100, and more preferably less than 50, e.g., 20 or less, forgeneral formula IV. The value of subscript s may range between anycombination of these values, inclusive of the recited values, e.g., smay be a number from 1 to 100. Subscript p may be 0, or may have a valueof at least 1, and preferably at least 5. Subscript p also typically hasa value of less than 300, preferably less than 100, and more preferablyless than 50, e.g., 20 or less. The value of subscript p may rangebetween any combination of these values, inclusive of the recitedvalues, e.g., p may be a number from 0 to 50.

[0061] The copolymer can have any suitable number average molecularweight (Mn). Suitable number average molecular weights can be from 5,000to 50,000, preferably from 12,000 to 40,000 most preferably from 17,000to 30,000, as determined by gel permeation chromatography usingpolystyrene standards. The polydispersity index, i.e., weight averagemolecular weight (Mw) divided by Mn, of the graft portion of thecopolymer is typically less than 2.0, e.g., less than 1.8 or less than1.5.

[0062] Symbol φ of general formula I is, or is derived from, the residueof the initiator used in the preparation of the copolymer by controlledradical polymerization, and is free of the radically transferable group(dormant halide) of the initiator.

[0063] The symbol φ may also represent a derivative of the residue ofthe initiator. For example, if the initiators have oxyranylgroup-containing moieties grafted thereto, the oxyranyl groups may bereacted either prior to or after the completion of the controlledradical polymerization with a carboxylic acid group-containing material.Classes of carboxylic acid group-containing materials with whichoxyranyl functional initiators or their residues may be reacted include,for example, aromatic carboxylic acids, polycyclic aromatic carboxylicacids, aliphatic carboxylic acids having from 6 to 20 carbon atoms, andmixtures thereof. Specific examples of carboxylic acid group-containingmaterials with which oxyranyl functional initiators or their residuesmay be reacted may include, but are not limited to, para-nitrobenzoicacid, hexanoic acid, 2-ethyl hexanoic acid, decanoic acid, undecanoicacid and mixtures thereof.

[0064] In another embodiment of the present invention, a segment of thecopolymer, i.e., the -(A)_(p)- segment in general formula IV can serveas a linking segment between the hydrophobic residue of the initiator,i.e., φ- in general formula IV, and a hydrophilic segment, i.e., the—(B)_(n)— segment in general formula IV. In reference to general formulaIV, A may be a residue of C₁-C₄ alkyl(meth)acrylates. Examples of C₁-C₄alkyl(meth)acrylates of which A may be a residue include,methyl(meth)acrylate, ethyl(meth)acrylate, propyl (meth)acrylate,isopropyl(meth)acrylate, n-butyl (meth)acrylate, isobutyl(meth)acrylate,tert-butyl (meth)acrylate and mixtures thereof.

[0065] Hydrophilic segments, i.e., —(B)_(s)— in reference to generalformula IV, may have nonionic moieties, ionic moieties and combinationsthereof. The segment can comprise residues of a monomer selected from,for example, poly(alkylene glycol) (meth)acrylates; C₁-C₄ alkoxypoly(alkylene glycol) (meth)acrylates; hydroxyalkyl(meth)acrylateshaving from 2 to 4 carbon atoms in the alkyl group; N-(hydroxy C₁-C₄alkyl) (meth)acrylamides (e.g., N-hydroxymethyl(meth)acrylamide andN-(2-hydroxyethyl) (meth)acrylamide); N,N-di-(hydroxy C₁-C₄ alkyl)(meth)acrylamides (e.g., N,N-di(2-hydroxyethyl) (meth)acrylamide);carboxylic acid functional monomers; salts of carboxylic acid functionalmonomers; amine functional monomers; salts of amine functional monomers;and mixtures thereof.

[0066] Hydrophilic segments including poly(alkylene glycol)(meth)acrylates and C₁-C₄ alkoxy poly(alkylene glycol) (meth)acrylatesmay be prepared by known methods. For example, (meth)acrylic acid orhydroxyalkyl(meth)acrylate, e.g., 2-hydroxyethyl(meth)acrylate, may bereacted with one or more alkylene oxides, e.g., ethylene oxide,propylene oxide and butylene oxide. Alternatively, analkyl(meth)acrylate may be transesterified with a C₁-C₄ alkoxypoly(alkylene glycol), e.g., methoxy poly(ethylene glycol). Examples ofpreferred poly(alkylene glycol) (meth)acrylates and C₁-C₄ alkoxypoly(alkylene glycol) (meth)acrylates include, poly(ethylene glycol)(meth)acrylate and methoxy poly(ethylene glycol) (meth)acrylate, thepoly(ethylene glycol) moiety of each having a molecular weight of from100 to 800. An example of a commercially available C₁-C₄ alkoxypoly(alkylene glycol) (meth)acrylate is methoxy poly(ethylene glycol)550 methacrylate monomer from Sartomer Company, Inc.

[0067] A segment of the copolymer may include carboxylic acid functionalmonomers which include, but are not limited to, (meth)acrylic acid,maleic acid, fumaric acid and undecylenic acid. For instance, in generalformula IV, B may initially be a residue of a precursor of a carboxylicacid functional monomer that is converted to a carboxylic acid residueafter completion of the controlled radical polymerization, e.g., maleicanhydride, di(C₁-C₄ alkyl) maleates and C₁-C₄ alkyl (meth)acrylates. Forexample, residues of maleic anhydride can be converted to diacidresidues, ester/acid residues or amide/acid residues by art-recognizedreactions with water, alcohols or primary amines, respectively. Residuesof C₁-C₄ alkyl(meth)acrylates, such as t-butyl methacrylate, can beconverted to (meth)acrylic acid residues by art-recognized esterhydrolyzation methods, which typically involve the concurrent removal ofan alcohol, such as t-butanol by vacuum distillation. Salts ofcarboxylic acid functional monomers include, for example, salts of(meth)acrylic acid and primary, secondary or tertiary amines, such as,butyl amine, dimethyl amine and triethyl amine.

[0068] The copolymer may contain a segment that contains aminefunctional monomers which include, for example, amino(C₂-C₄ alkyl)(meth)acrylates, e.g., 2-aminoethyl(meth)acrylate,3-aminopropyl(meth)acrylate and 4-aminobutyl(meth)acrylate; N(C₁-C₄alkyl)amino(C₂-C₄ alkyl) (meth)acrylates, e.g.,N-methyl-2-aminoethyl(meth)acrylate; and N,N-di(C₁-C₄ alkyl)amino(C₂-C₄alkyl) (meth)acrylates, e.g., N,N-dimethyl-2-aminoethyl (meth)acrylate.A segment may also comprise residues of salts of amine functionalmonomers, e.g., salts of those amine functional monomers as recitedpreviously herein. Salts of the amine functional monomer residues may beformed by mixing a carboxylic acid, e.g., lactic acid, with thecopolymer after completion of controlled radical polymerization.

[0069] In one embodiment of the copolymer, a segment contains carboxylicacid functional monomers selected from (meth)acrylic acid, maleicanhydride, maleic acid, di(C₁-C₄ alkyl) maleates, and mixtures thereof.In a still further embodiment of the present invention, amine functionalmonomers are selected from amino(C₂-C₄ alkyl) (meth)acrylates, N-(C₁-C₄alkyl)amino(C₂-C₄ alkyl) (meth)acrylates, N,N-di(C₁-C₄ alkyl)amino(C₂-C₄alkyl) (meth)acrylates and mixtures thereof.

[0070] A segment of the copolymer may also contain cationic moietiesselected from ammonium, sulphonium and phosphonium. Ammonium, sulphoniumand phosphonium moieties may be introduced into the graft copolymer bymeans known to the skilled artisan. For example, when a segment containsN,N-dimethyl-2-aminoethyl(meth)acrylate monomers, the N,N-dimethylaminomoieties may be converted to ammonium moieties by mixing an acid, e.g.,lactic acid, with the graft copolymer.

[0071] When a segment of the copolymer contains residues of oxiranefunctional monomers, such as glycidyl(meth)acrylate, the oxirane groupsmay be used to introduce sulphonium or phosphonium moieties into thecopolymer. Sulphonium moieties may be introduced into the copolymer byreaction of the oxirane groups with thiodiethanol in the presence of anacid, such as lactic acid. Reaction of the oxirane groups with aphosphine, e.g., triphenyl phosphine or tributyl phosphine, in thepresence of an acid, such as lactic acid, results in the introduction ofphosphonium moieties into the copolymer.

[0072] Other reactive groups, such as carbamate groups, can beincorporated into the copolymer. Carbamate groups, may be introduced byincluding in the ATRP reaction mixture monomers that include carbamategroups and/or by post-reacting the copolymer to add a carbamate group.For instance, carbamate functional groups can be incorporated into thecopolymer by reacting a hydroxyl functional acrylic moiety with a lowmolecular weight alkyl carbamate such as methyl carbamate. Hydroxylfunctional acrylic moieties also can be reacted with isocyanic acid toprovide pendant carbamate groups. Likewise, hydroxyl functionalcopolymers can be reacted with urea to provide pendant carbamate groups.

[0073] In a preferred embodiment of the present invention, the radicallytransferable group is a halide group. Dormant halogens can be removedfrom the terminus of the graft copolymer by any manner known in the art,such as by HX abstraction. Typically the dormant halogen is removed bymeans of a mild dehalogenation reaction, that typically is performed asa post-reaction after the graft copolymer has been formed, and in thepresence of at least an ATRP catalyst. Preferably, the dehalogenation isperformed in the presence of both an ATRP catalyst and its associatedligand.

[0074] As discussed above, the ATRP process can be conducted with asequence of monomers to produce a defined copolymer. Thus, the choice ofmonomers and the sequence of their reaction with dormant halide groupsof the initiator and/or propagating chain will influence the finalstructure of the copolymer. The choice of macroinitiator also willdictate the physical structure of the copolymer. For instance,initiation with certain dormant halides will be more favorable thanothers. The degree of branching of the macroinitiator also will affectthe final structure of the copolymer. Since the dormant halide groups ofthe macroinitiator are pendant, grafted linear portions of thepolyolefin backbone will have a comb-like structure. Macroinitiatorswith branched structures will yield a more complex, branched copolymerwith both comb-like sections, corresponding to relatively linearportions of the backbone, and star-like sections that are the result ofgrafting onto a tertiary carbon at a branch point between linearportions of the polyolefin backbone. The average weight of themacroinitiator also will dictate the complexity of the resultantcopolymer. Lastly, the number of dormant halides on the polyolefinbackbone, i.e., the weight percent of active halide groups in theinitiator, will effect the structure of the copolymer.

[0075] The copolymer prepared according to the methods of the presentinvention is a copolymer having a polyolefinic backbone and one or morepolymer blocks prepared according to the above-described process.

[0076] Thus, the copolymer of the present invention includes apolyolefin backbone with pendant halide groups and pendant polymericblocks of radically polymerizable alkenes containing a polar group thatare attached to tertiary carbons of the backbone. The blocks may be ofthe same monomer, but preferably are of two or more different monomers.The blocks may be homopolymeric or copolymeric. The blocks typically areattached sequentially to the polyolefin backbone, as in generalstructure (IX):

PO-(A-B—X)_(n)  (IX)

[0077] Where PO is the backbone, n is an integer greater than 0, A is afirst block of monomers, B is a second block of monomers and X is adormant halide. The monomer content of each of block A and B differ. By“monomer content” it is meant both the type of monomer, i.e., GMA vs.MMA, and the relative ratio of the monomers, by weight, in each block.It should be noted that in certain circumstances, even though blocks ofA are attached directly to the backbone, blocks of B may also beattached directly to the backbone. This can result from the incompleteuse of dormant halides on the backbone. In such a case, at least threetypes of grafts exist, according to the following: -A-X. -A-B—X and—B—X, each of which may exist on the same or different backbone. Therelative amount of each of these grafts will depend on the reactionconditions and structure of the initiator, and is dependent upon therelative initiation and propagation contents for the respective dormanthalides and monomers chosen under the specific reaction conditions.

[0078] In one embodiment of the present invention, the copolymer is usedas an additive for a film-forming composition. The additive promotesadhesion of the film-forming composition to a polyolefinic substrate,thereby preventing delamination of the film-forming composition from thesubstrate.

[0079] The copolymer typically is present in the film-formingcomposition in an amount of at least 1.5% by weight, preferably at least3% by weight, and more preferably at least 5% by weight, based on thetotal weight of the resin solids other than the copolymer in thefilm-forming composition. The copolymer is also typically present in thefilm-forming composition in an amount of less than 20% by weight,preferably less than 5% by weight, and more preferably less than 3% byweight, based on the total weight of the resin solids in thefilm-forming composition. The amount of copolymer present in thefilm-forming composition of the present invention may range between anycombination of these values, inclusive of the recited values.

[0080] Nevertheless, depending upon the structure of the copolymer, andthe active groups present thereon, the copolymer can serve as a primaryfilm-forming resin in a coating. In this particular embodiment, thegraft copolymer is typically present in the film forming composition inan amount of about 50% to 100% by weight, preferably 45% to 100% byweight.

[0081] A crosslinking agent typically is present in the film-formingcomposition. Generally, the crosslinking agent is an aminoplast or anisocyanate. An aminoplast crosslinking agent is commonly a partially orfully alkylated aminoplast crosslinking agent. The aminoplastcrosslinking agent can have a plurality of functional groups, forexample, alkylated methylol groups, that are reactive with the pendantcarbamate groups present in the acrylic, polyester, polyurethane orpolyether polymer.

[0082] Aminoplast resins, which include phenoplasts, as curing agentsfor hydroxyl, carboxylic acid and carbamate functional group-containingmaterials are well-known in the art. Aminoplast crosslinking agents areobtained from the reaction of formaldehyde with an amine and/or anamide. Melamine, urea, or benzoguanamine condensates are preferred.However, aminoplast condensates prepared from other amines or amides canbe used, for example, aldehyde condensates of glycouril, which areuseful in formulating powder coatings. Most often, formaldehyde is usedas the aldehyde; however, other aldehydes such as acetaldehyde,crotonaldehyde, and benzaldehyde are also suitable.

[0083] By the term “fully alkylated” it is meant that the alkylol groupsassociated with the reaction product of an aldehyde with an amine and/oran amide have been etherified to an extent that the alkoxy groups makeup at least 80% by weight of the functional groups.

[0084] A preferred aminoplast crosslinking agent is amelamine-formaldehyde condensate that has been fully alkylated, that is,the melamine-formaldehyde condensate contains methylol groups that havebeen further etherified with an alcohol, preferably one that contains 1to 6 carbon atoms. Any monohydric alcohol can be employed forthis-purpose, including methanol, ethanol, n-butanol, isobutanol, andcyclohexanol. Most preferably, a blend of methanol and n-butanol isused. Suitable aminoplast resins are commercially available from CytecIndustries, Inc. under the trademark CYMEL® and from Solutia, Inc. underthe trade name RESIMENE®.

[0085] The aminoplast curing agent is typically present in thecompositions of the invention in an amount ranging from 2 to 60 wt. %,preferably from 10 to 50 wt. %, and more preferably from 15 to 45 wt. %based on the total weight of resin solids in the composition.

[0086] The curing agent may also be a polyisocyanate that optionally canbe added as an adjuvant curing agent, along with an aminoplast. As usedherein and in the claims, the term “polyisocyanate” is intended toinclude blocked (or capped) polyisocyanates as well as unblockedpolyisocyanates. The polyisocyanate can be an aliphatic or an aromaticpolyisocyanate or a mixture of the two. Diisocyanates may be used,although higher polyisocyanates such as isocyanurates of diisocyanatesare preferred. Higher polyisocyanates can also be used in combinationwith diisocyanates. Isocyanate prepolymers, for example, reactionproducts of polyisocyanates with polyols, can also be used. Mixtures ofpolyisocyanate curing agents can be used.

[0087] Examples of suitable aliphatic diisocyanates are straight-chainaliphatic diisocyanates such as 1,4-tetramethylene diisocyanate and1,6-hexamethylene diisocyanate. Also, cycloaliphatic diisocyanates canbe employed. Examples include isophorone diisocyanate and4,4′-methylene-bis(cyclohexyl isocyanate). Examples of suitable aromaticdiisocyanates are p-phenylene diisocyanate,diphenylmethane-4,4′-diisocyanate and 2,4- or 2,6-toluene diisocyanate.Other diisocyanates include 1,3-bis(1-isocyanato-1-methylethyl)benzene.Examples of suitable higher polyisocyanates aretriphenylmethane-4,4 ,4″-triisocyanate, 1,2,4-benzene triisocyanate andpolymethylene polyphenyl isocyanate. Other polyisocyanates includebiurets and isocyanurates of diisocyanates, including mixtures thereof,such as the isocyanurate of hexamethylene diisocyanate, the biuret ofhexamethylene diisocyanate, and the isocyanurate of isophoronediisocyanate. Isocyanate prepolymers, for example, reaction products ofpolyisocyanates with polyols such as neopentyl glycol and trimethylolpropane or with polymeric polyols such as polycaprolactone diols andtriols (NCO/OH equivalent ratio greater than one), can also be used.

[0088] If the polyisocyanate is blocked or capped, any suitablealiphatic, cycloaliphatic, or aromatic alkyl monoalcohol known to thoseskilled in the art can be used as a capping agent for the polyisocyanateincluding, for example, lower aliphatic alcohols such as methanol,ethanol, and n-butanol; cycloaliphatic alcohols such as cyclohexanol;aromatic-alkyl alcohols such as phenyl carbinol and methylphenylcarbinol; and phenolic compounds such as phenol itself and substitutedphenols wherein the substituents do not affect coating operations, suchas cresol and nitrophenol.

[0089] Glycol ethers may also be used as capping agents. Suitable glycolethers include ethylene glycol butyl ether, diethylene glycol butylether, ethylene glycol methyl ether and propylene glycol methyl ether.Other suitable capping agents include oximes, pyrazoles and lactams. Oneparticular example is isophorone diisocyanate capped with methyl ethylketoxime.

[0090] When used, the polyisocyanate curing agent is present in anamount ranging from 1 to 40 wt. %, preferably from 1 to 20 wt. %, morepreferably 1 to 10 wt. % based on the total weight of resin solids inthe film-forming composition.

[0091] Examples of other blocked polyisocyanates include triazinecompounds having the formula C₃N₃(NHCOXR)₃, wherein X is nitrogen,oxygen, sulfur, phosphorus, or carbon, and R is an alkyl group havingone to twelve, preferably one to four, carbon atoms, or mixtures of suchalkyl groups. X is preferably oxygen or carbon, more preferably oxygen.R preferably has one to eight carbon atoms, for example, methyl, ethyl,n-propyl, isopropyl, butyl, n-octyl and 2-ethylhexyl. R is preferably amixture of methyl and butyl groups. Such compounds, and the preparationthereof, are described in detail throughout U.S. Pat. No. 5,084,541,incorporated herein by reference. Examples of triazine compounds aretris carbamoyl triazine or 1,2,5 triazine-2,4,6 tris-carbamic acidesters. When used, the triazine curing agent is present in thefilm-forming composition in an amount ranging from 1 to 40 wt. %,preferably from 1 to 20 wt. %, more preferably 1 to 10 wt. % based onthe total weight of resin solids in the film-forming composition.

[0092] Optionally, a diluent can be present in the film-formingcomposition, that serves to reduce the viscosity of the coatingcomposition. If the coating composition is solvent-borne, the diluenttypically comprises an organic solvent. Examples of suitable solventsinclude alcohols such as ethanol, isopropanol, n-butanol, and the like;esters such as n-butyl acetate, n-hexyl acetate, pentyl propionate, andthe like; ethers such as the monoethyl, monobutyl and monohexyl ethersof ethylene glycol and propylene glycol, and the like; ketones such asmethyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and thelike; aromatic hydrocarbons such as xylene, or toluene, and the like;aliphatic or alicyclic hydrocarbons such as the various petroleumnaphthas and cyclohexane; and mixtures thereof.

[0093] When present, diluents are typically used at a level of up toabout 97% by weight based on the total weight of the film-formingcomposition.

[0094] The film-forming composition can also be used in particulateform, i.e., as a powder coating, in which the acrylic polymer and theoligomer or polymer containing the repeating ester groups are chosensuch that they have a glass transition temperature (Tg) greater than 60°C. These materials can then be combined with an aldehyde condensate ofglycouril, as previously mentioned, to form a powder film-formingcomposition.

[0095] The film-forming composition is typically a thermosettingcomposition and typically contains catalysts to accelerate the curingreactions. Typically, the catalysts are acidic materials. Sulfonicacids, substituted sulfonic acids and amine neutralized sulfonic acidsare preferred, for example, p-toluene sulfonic acid, dodecyl benzenesulfonic acid, dinonylnaphthalene disulfonic acid, and the like. Thecatalyst is usually present in an amount of from 0.3 to 5.0 percent,preferably from 0.5 to 1.0 percent, the percentages based on the totalweight of resin solids in the coating composition.

[0096] The film-forming composition can contain other optionalingredients, such as co-reactive resinous materials, plasticizers,anti-oxidants, UV light absorbers, surfactants, flow control agents,anti-settling agents, and the like. When present, these materials aregenerally used at a level of less than 25%, preferably less than 10% byweight, the percentages based on the total weight of resin solids in thecoating composition. The coating composition can also contain pigment.

[0097] The film-forming composition containing additive quantities ofthe copolymer is applied to a polyolefinic substrate directly. However,since the physical characteristics of the copolymer of the presentinvention can vary broadly, the copolymer may be present in othercoating layers or can find use for purposes other than promotingadhesion to a polyolefinic substrate. In that case, the coating can beapplied to any of the various substrates to which it adheres. Specificexamples of suitable substrates include metals, wood, glass, cloth,plastic, foam, elastomeric substrates, and the like. Typically, thesubstrate is metal or plastic and, most typically, a polyolefinicplastic. Optionally, the substrate could have been previously coatedwith an electrocoat primer and/or a primer surfacer and/or a pigmentedbasecoat and the film-forming composition of the present inventionapplied as a clear coat over the pigmented base coat to form a colorplus clear composite coating.

[0098] The compositions can be applied by conventional means includingbrushing, dipping, flow coating, spraying, and the like. Preferably,they are applied by spraying. The usual spray techniques and equipmentfor air-spraying or electrostatic spraying can be used.

[0099] The copolymers of the present invention find use in many fields,such as in coating compositions, compositions for molding, extruding andother article fabrication processes, healthcare and personal carecompositions and in any other application for polymeric compounds.

[0100] The present invention is more particularly described in thefollowing examples, which are intended to be illustrative only, sincenumerous modifications and variations therein will be apparent to thoseskilled in the art. Unless otherwise specified, all parts andpercentages are by weight.

A. SYNTHESIS EXAMPLES Example 1 Synthesis of Graft Copolymer ChlorinatedPolyolefin (CPO)-GMA-MMA

[0101] Glycidyl methacrylate (GMA) and methyl methacrylate (MMA)residues were copolymerized using a CPO initiator according to thefollowing: TABLE A Ingredients Parts by weight (grams) Charge 1 Xylene588.90 Copper 0.64 2,2′-Bypyridyl 1.09 Magnesol¹ 20 CP343-1 CPO² 250(solid) GMA 42.60 Charge 2 MMA 100

[0102] Charge 1 was heated in a reaction vessel with agitation at 85° C.and the reaction mixture was held at this temperature for 2 hours. Thecharge 2 was added over a period of 15 minutes. The reaction mixture washeld at 85° C. for 3 hours. The reaction mixture was cooled andfiltered. The resultant graft copolymer had a total solid content of41.3% determined at 110° C. for one hour. The copolymer had numberaverage molecular weight, Mn=20,320 and polydispersity Mw/Mn=2.57(determined by gel permeation chromatography using polystyrene as astandard). The chlorinated polyolefin (CP343-1) macroinitiator hadnumber average molecular weight, Mn=13,950 and polydispersity Mw/Mn=2.20(determined by gel permeation chromatography using polystyrene as astandard). The ¹H NMR spectrum is fully consistent with graft-copolymerCPO-GMA-MMA, exhibiting all key absorption of monomers used and the peakarising from macroinitiator. DSC data show for the graft copolymeryielded a melting point of Tm=98° C., and percentage of crystallinity Wc˜1%.

Example 2 Synthesis of Graft Copolymer Chlorinated Polyolefin(CPO)-GMA/Neodecanoic Acid-MMA

[0103] An adduct of GMA and neodecanoic acid (GMA/neodecanoic acid) andMMA residues were copolymerized using a CPO initiator according to thefollowing: TABLE B Ingredients Parts by weight (grams) Charge 1 Xylene588.9 Copper (II) bromide 0.11 Copper 0.06 2,2′-Bypyridyl 0.11 Magnesol20 CP343-1 CPO 250 GMA/Neodecanoic acid¹ 94.82 Charge 2 MMA 100

[0104] Charge 1 was heated in a reaction vessel with agitation at 85° C.and the reaction mixture was held at this temperature for 2 hours. Thecharge 2 was added over a period of 15 minutes. The reaction mixture washeld at 85° C. for 3 hours. The reaction mixture was cooled andfiltered. The resultant graft copolymer had a total solid content of44.2% determined at 110° C. for one hour. The copolymer had numberaverage molecular weight, Mn=15,790 and polydispersity Mw/Mn=2.79(determined by gel permeation chromatography using polystyrene as astandard). The chlorinated polyolefin (CP343-1) macroinitiator hadnumber average molecular weight, Mn=13,950 and polydispersity Mw/Mn=2.20(determined by gel permeation chromatography using polystyrene as astandard). The ¹H NMR spectrum is fully consistent with graft-copolymerCPO-GMA/neodecanoic acid-MMA, exhibiting all key absorption of monomersused and the peak arising from macroinitiator. DSC data show for thegraft copolymer yielded a melting point of Tm=87° C., and percentage ofcrystallinity Wc ˜4%.

Example 3 Synthesis of Graft Copolymer Chlorinated Polyolefin(CPO)-HPMA-MMA-HPMA

[0105] Hydroxypropyl methacrylate (HPMA) and MMA residues werecopolymerized using a CPO initiator according to the following: TABLE CIngredients Parts by weight (grams) Charge 1 Xylene 588.9 Copper (II)bromide 0.67 Copper 0.06 2,2′-Bypyridyl 0.11 Magnesol 20 CP343-1 CPO 250HPMA 21.60 Charge 2 MMA 100 Charge 3 HPMA 21.30

[0106] Charge 1 was heated in a reaction vessel with agitation at 85° C.and the reaction mixture was held at this temperature for 2 hours. Thecharge 2 was added over a period of 15 minutes. The reaction mixture washeld at 85° C. for 3 hours. The charge 3 was added over a period of 15minutes. The reaction mixture was held at 85° C. for 2 hours. Thereaction mixture was cooled and filtered. The resultant graft copolymerhad a total solid content of 41.0% determined at 110° C. for one hour.The copolymer had number average molecular weight, Mn=19,640 andpolydispersity Mw/Mn=3.0 (determined by gel permeation chromatographyusing polystyrene as a standard). The chlorinated polyolefin (CP343-1)macroinitiator had number average molecular weight, Mn=15,120 andpolydispersity Mw/Mn=2.30 (determined by gel permeation chromatographyusing polystyrene as a standard). The ¹H NMR spectrum is fullyconsistent with graft-copolymer CPO-HPMA-MMA-HPMA, exhibiting all keyabsorption of monomers used and the peak arising from macroinitiator.DSC data show for the graft copolymer yielded a melting point of Tm=91°C., and percentage of crystallinity Wc ˜3%.

Example 4 Synthesis of Graft Copolymer Chlorinated Polyolefin (CPO)-HPMA

[0107] HPMA residues were polymerized using a CPO initiator according tothe following: TABLE D Ingredients Parts by weight (grams) Charge 1Xylene 1177.80 Copper (II) bromide 1.34 Copper 0.34 2,2′-Bypyridyl 0.44Magnesol 40 CP343-1 CPO 500 HPMA 285.80

[0108] Charge 1 was heated in a reaction vessel with agitation at 85° C.and the reaction mixture was held at this temperature for 4 hours. Thereaction mixture was cooled and filtered. The resultant graft copolymerhad a total solid content of 41.3% determined at 110° C. for one hour.The copolymer had number average molecular weight, Mn=20,380 andpolydispersity Mw/Mn=3.0 (determined by gel permeation chromatographyusing polystyrene as a standard). The chlorinated polyolefin (CP343-1)macroinitiator had number average molecular weight, Mn=15,120 andpolydispersity Mw/Mn=2.30 (determined by gel permeation chromatographyusing polystyrene as a standard). The ¹H NMR spectrum is fullyconsistent with graft-copolymer CPO-HPMA, exhibiting all key absorptionof monomer used and the peak arising from macroinitiator. DSC data showfor the graft copolymer yielded a melting point of Tm=87° C., andpercentage of crystallinity Wc ˜2%.

Example 5 Synthesis of Graft Copolymer Chlorinated Polyolefin(CPO)-HPMA-MAA/Cardura E-HPMA

[0109] HPMA and an adduct of Cardura E and methacrylic acid (MAA/CarduraE) were copolymerized using a CPO initiator according to the following:TABLE E Ingredients Parts by weight (grams) Charge 1 Xylene 422.6Cardura E 100 Copper 0.75 2,2′-Bypyridyl 2.5 CP343-1 CPO 250 HPMA 28.80Charge 2 MAA/Cardura E¹ 135.20 Charge 3 HPMA 43.20

[0110] Charge 1 was heated in a reaction vessel with agitation at 80° C.and the reaction mixture was held at this temperature for 1 hour. Thecharge 2 was added over a period of 15 minutes. The reaction mixture washeld at 80° C. for 3 hours. The charge 3 was added over a period of 15minutes. The reaction mixture was held at 85° C. for 3 hours. Thereaction mixture was cooled and filtered. The resultant graft copolymerhad a total solid content of 46.6% determined at 110° C. for one hour.The copolymer had number average molecular weight, Mn=21,660 andpolydispersity Mw/Mn=3.0 (determined by gel permeation chromatographyusing polystyrene as a standard). The chlorinated polyolefin (CP343-1)macroinitiator had number average molecular weight, Mn=15,120 andpolydispersity Mw/Mn=2.30 (determined by gel permeation chromatographyusing polystyrene as a standard). The ¹H NMR spectrum is fullyconsistent with graft-copolymer CPO-HPMA-MAA/Cardura E-HPMA, exhibitingall key absorption of monomers used and the peak arising frommacroinitiator.

B. COATING EXAMPLES Example 6 Use of the Resin of Example 5 in anAdhesion Promoting Coating Layer

[0111] The resin of Example 5 was evaluated as a low solids, directsubstrate adhesion promoter (Coating A). Adhesion to various substrateswas compared to the CPO precursor material (Coating B), and a commercialadhesion promoter (DPX-801, PPG Industries, Inc.) (Coating C). TABLE FCoating A Coating B Component weight (g) weight (g) Resin of Example 519.9 — CP343-1 CPO — 12.5 Xylene +TA,17/20 +UZ,80.1 87.5 Total 100.0100.0

[0112] Plastic substrates were cleaned and abraded using water, anabrasive detergent (DX101, PPG Industries, Inc.), and an abrasive pad(gray Scotch-Brite™, 3M). After rinsing with water and subsequentdrying, the substrates were wiped with two additional solvent-basedcleaners (DX330, PPG Industries, Inc., DX103 PPG Industries, Inc.).

[0113] Coatings A, B, and C were applied directly to the cleaned plasticsubstrates (˜0.1-0.2 DFT), followed by primer sealer (K36, PPGIndustries, Inc.), basecoat (DBC4037, PPG Industries, Inc.), andclearcoat (DCU2042, PPG Industries, Inc.) coating layers. Coatedsubstrates were cured at ambient temperature.

[0114] Coating adhesion was evaluated using a Crosshatch adhesion test.Using a multi-blade cutter (Paul N. Gardner Company, Inc.), coatedpanels were scribed twice (at 90°), making sure the blades cut throughall coating layers into the substrate. Coating adhesion was measuredusing Nichiban L-24 tape (four pulls at 90°). Adhesion was rated on a0-5 scale (5=100% adhesion, 0=0% adhesion). Failure mode was adhesivebetween the substrate and adhesion promoter, unless otherwise noted inthe results.

[0115] Adhesion measurements were taken one and seven days afterapplication. Additional samples were aged for seven days, then exposedto elevated temperature and humidity (100° C./100% for four days).Adhesion was evaluated immediately and one day after exposure. Adhesionresults are summarized in Table G below. Grafting to the CPO (as inExample 5) does not negatively effect adhesion to the various plasticsubstrates. Additionally, performance of the resin of Example 5 issimilar to the commercial adhesion promoter. TABLE G Adhesion AdhesionAdhesion Adhesion 1 Hour after 1 Day after 1 Day 7 Day Exposure²Exposure² Substrate¹ (0-5) (0-5) (0-5) (0-5) Coating A Bayflex 110-35 44 4 4 Sequel 1440 4 4 4 4 Montell CA186 4 4 4 4 TSOP-1 4 4 4 4 HimontSD242 5 5 5 4 Coating B Bayflex 110-35 4 4 4 4 Sequel 1440 4 4 4 4Montell CA186 4 4 4 4 TSOP-1 4 4 4 4 Himont SD242 5 4 5 3 Coating CBayflex 110-35 4 4 4 4 Sequel 1440 4 4 4 4 Montell CA186 4 4 4 4 TSOP-14 4 4 4 Himont SD242 5 5 5 4

Example 7 Use of the Polymer of Example 5 as an Adhesion-PromotingIngredient in a Primer-Sealer—Comparison to Commercially AvailableAdhesion-Promoting Layer

[0116] The resin of Example 5 was evaluated as an adhesion-promotingingredient in a primer sealer for plastic substrates (Coating D).Pigmentation was dispersed into the resin of Example 5 by milling. TABLEH Coating D 9 Component weight (g) Resin of Example 5 214.4Disperbyk-110¹ 5.5 Talc Pigment 25.0 TiO₂ Pigment 25.0 Barium Sulfate25.0 Pigment Black Tint Paste 1.0 Toluene 101.1 Butyl acetate 103.0Total 500.0

[0117] Plastic substrates were cleaned as described in Example 6.Coating D was applied directly to the various plastic substrates,followed by basecoat (DBC4037, PPG Industries, Inc.) and clearcoat(DCU2042, PPG Industries, Inc.) coating layers. Additionally, acommercial system was evaluated. Adhesion promoter (Coating E) (DPX-801,PPG Industries, Inc.) was applied directly to the cleaned substrates,followed by primer sealer (K36, PPG Industries, Inc.), basecoat(DBC4037, PPG Industries, Inc.), and clearcoat (DCU2042, PPG Industries,Inc.) coating layers. Coated substrates were cured at ambienttemperature.

[0118] Coating adhesion was tested as described in Example 6. Theresults in Table I indicate that primer sealer prepared from the resinof Example 5 (Coating D) provides similar adhesion to the commercialsystem (Coating E), without use of a separate adhesion promoter layer.TABLE I Adhesion Adhesion Adhesion Adhesion 1 Hour after 1 Day after 1Day 7 Day Exposure² Exposure² Substrate¹ (0-5) (0-5) (0-5) (0-5) CoatingD Bayflex 110-35  3³ 4 4 4 Sequel 1440 4 4 4 4 Montell CA186 4 4 4 4TSOP-1 4 4 4 4 Himont SD242  3³ 5 4 4 Coating E Bayflex 110-35 4 4 4 4Sequel 1440 4 4 4 4 Montell CA186 4 4 4 4 TSOP-1 4 4 4 4 Himont SD242 44 4 4

Example 8 Use of the Resin of Example 5 as an Adhesion-PromotingAdditive for a Primer-Sealer

[0119] The resin of Example 5 was evaluated as an adhesion-promotingadditive for an existing primer sealer system. Experimental coatingswere formulated containing 0, 5, 10 or 20 wt. % CPO based on resinsolids. TABLE J Coating F Coating G Coating H Coating I Component Weight(g) weight (g) weight (g) weight (g) K36 Prima¹ 99.8 99.8 99.8 99.8DCU2021² 31.7 23.4 15.0 — Resin of — 19.0 38.0 72.0 Example 5 Xylene —30.0 25.0 35.0 DT870³ 27.6 — — — DCX8⁴ 17.9 17.9 17.9 17.9 Total 177.0190.1  195.7  224.7 

[0120] Coatings F-I were applied directly to cleaned plastic substrates(see Example 6), followed by basecoat (DBC4037, PPG Industries, Inc.)and clearcoat (DCU2042, PPG Industries, Inc.) layers. Additionally, aCoating J was prepared, wherein the cleaned substrate was coated with acommercial adhesion promoter (DPX-801, PPG Industries, Inc.), a primersealer (K36, PPG Industries, Inc.), a basecoat (DBC4037, PPG Industries,Inc.), and a clearcoat (DCU2042, PPG Industries, Inc.). All coatedsubstrates were cured at ambient temperature. The adhesion properties ofthe coatings are summarized in Table K. TABLE K Adhesion AdhesionAdhesion Adhesion 1 Hour after 1 Day after Coating Sub- 1 Day 7 DayExposure² Exposure² Example strate¹ (0-5) (0-5) (0-5) (0-5) Coating FBayflex 4 4 3 3 110-35 Sequel 0 0 0 0 1440 Montell 0 0 0 0 CA186 TSOP-11 0 0 0 Himont 0 0 0 0 SD242 Coating G Bayflex 4 4 3 3 110-35 Sequel 3 34 2 1440 Montell 4 3 4 3 CA186 TSOP-1 4 3 4 3 Himont 4 4 3 0 SD242Coating H Bayflex 4 4 3 4 110-35 Sequel 4 4 4 3 1440 Montell 4 3 4 3CA186 TSOP-1 4 4 4 3 Himont 4 4 4 4 SD242 Coating I Bayflex 4 4 3 3110-35 Sequel 4 4 4 2 1440 Montell 4 3 3 3 CA186 TSOP-1 4 4 4 3 Himont 44 4 3 SD242 Coating J Bayflex 4 4 3 3 110-35 Sequel 4 3 4 3 1440 Montell4 3 4 3 CA186 TSOP-1 4 3 4 3 Himont 4 4 4 3 SD242

[0121] The data in Table K demonstrate that the copolymer of the presentinvention is comparable to commercially available adhesion promoters inits adhesion promoting activities.

[0122] C. Comparison of ATRP Using a CPO Initiator vs. a ConventionalFree Radical Polymerization Process

[0123] For comparison of the process for the present invention and U.S.Pat. No. 5,955,545, copolymers were prepared according to the process ofthe present invention (Example 9) and U.S. Pat. No. 5,955,545 (Example10).

Example 9 Synthesis by ATRP of Graft Copolymer CPO-CHMA/BMA/IBMA/HPMA

[0124] Cyclohexyl methacrylate (CHMA), butyl methacrylate (BMA),isobutyl methacrylate (IBMA) and HPMA were copolymerized using a CPOinitiator according to the following: TABLE L Ingredients Parts byweight (grams) Charge 1 Xylene 100.00 Copper 0.60 2,2′-Bypyridyl 2.00Cardura E 30.00 CP515-2 CPO¹ 195.3 (40% TS in xylene) CHMA 150.00 BMA52.50 IBMA 70.00 HPMA 285.80

[0125] Charge 1 was heated in a reaction vessel with agitation at 85° C.and the reaction mixture was held at this temperature for seven hours.The reaction mixture was cooled and filtered. The resultant graftcopolymer had a total solid content of 61.7% determined at 110° C. forone hour. The copolymer had number average molecular weight, Mn=39735and polydispersity Mw/Mn=3.0 (determined by gel permeationchromatography using polystyrene as a standard). The chlorinatedpolyolefin (CP515-2) macroinitiator had number average molecular weight,Mn=19390 and polydispersity Mw/Mn=2.30 (determined by gel permeationchromatography using polystyrene as a standard). The ¹H NMR spectrum isfully consistent with graft-copolymer CPO-CHMA/BMA/IBMA/HPMA, exhibitingall key absorption of monomers used and the peak arising from themacroinitiator. DSC data show for graft copolymer a glass transitiontemperature Tg=24° C. (CP 515-2 had Tg=0.7° C.).

Example 10 Synthesis by Free Radical Polymerization of CopolymerCPO/CHMA/BMA/IBMA/HPMA

[0126] CHMA, BMA, IBMA and HPMA residues were copolymerized using ahalogenated CPO initiator according to the following: TABLE MIngredients Parts by weight (grams) Charge 1 Xylene 100.00 CP515-2 CPO195.3 (40% TS in xylene) Charge 2 VAZO 64¹ 1.00 CHMA 150.00 BMA 52.50IBMA 70.00 HPMA 285.80 Charge 3 VAZO 64 1.00

[0127] Charge 1 was heated in a reaction vessel with agitation at 100°C. and to the reaction mixture was added charge 2 over a two hourperiod. At the end of the feed, the temperature was dropped to 80° C.,and than charge 3 was added. The reaction mixture was held for fivehours at 80° C. The reaction mixture was cooled and filtered. Theresultant graft copolymer had a total solid content of 61.7% determinedat 110° C. for one hour. The copolymer had number average molecularweight, Mn=19790 and polydispersity Mw/Mn=2.6 (determined by gelpermeation chromatography using polystyrene as a standard). Thechlorinated polyolefin (CP515-2) macroinitiator had number averagemolecular weight, Mn=19390 and polydispersity Mw/Mn=2.30 (determined bygel permeation chromatography using polystyrene as a standard). The ¹HNMR spectrum is fully consistent with copolymer CPO/CHMA/BMA/IBMA/HPMA,exhibiting all key absorption of monomers used and the peak arising fromthe macroinitiator. DSC data show for graft copolymer a glass transitiontemperature Tg=37.1° C. (CP 515-2 had Tg=0.7° C.), which differs fromthe Tg of the resin of Example 9 (24° C.).

Example 11 Comparison of Resin of Examples 9 and 10 to CPO asAdhesion-Promoting Layer

[0128] Physical properties of the resins of Examples 9 and 10, as wellas the precursor CPO material, were characterized using several testmethods. Results, as well as a description of the test methods, aresummarized in Table N. Physical properties clearly indicate that the twopolymerization methods result in two distinct polymers, with uniquechain architectures. Adhesion promoting compositions prepared usingresins prepared according to U.S. Pat. No. 5,955,545 (Example 10) wereless stable and hazy, indicating incompatibility.

[0129] The resins of Examples 9 and 10, as well as the CPO precursormaterial, were formulated as low solids, direct-to-substrate adhesionpromoters (Coatings K-M in Table O). Plastic substrates were prepared asoutlined in Example 6. Coatings K-M, as well as a commercial adhesionpromoter (Coating N, in Table P) (DPX-801, PPG Industries, Inc.), wereapplied to the cleaned substrates (−0.1-0.2 mil DFT). Subsequently,substrates were coated with primer sealer (K36, PPG Industries, Inc.),basecoat (DBC 4037, PPG Industries, Inc.), and clearcoat (DCU 2042, PPGIndustries, Inc.) coating layers. Coated substrates were cured atambient temperature.

[0130] Coating adhesion was evaluated as described in Example 6. Resultsare summarized in Table P. TABLE N Solid Resin Appearance Stability⁶Solids Equiv. Viscosity² of Resin Appearance of 39° F./ Tg⁷ Resin (%)Weight¹ (cps) Mn³ Solution Solid Film 120° F. (° C.) CPO 40   NA 3819390 Visual: Visual: Clear Pass/Pass −0.7 Precursor (theory) SlightlyUV/Vis. (Eastman Cloudy Extinction⁵: 1 515-2) Resin of 61.8 1500 6339730 Visual: Visual: Clear Pass/Pass 24.0 Example 9 (synthesis)(theory) Clear UV/Vis. 1351 Haze⁴: 18.63 Extinction⁵: <1  (actual) Resinof 68.6 1400 45 19730 Visual: Visual: Cloudy Fail (cloudy, 37.1 Example10 (synthesis) (theory) Cloudy UV/Vis. two layers)/Fail 1441 Haze⁴:58.01 Extinction⁵: >30 (two layers) (actual)

[0131] TABLE O Coating K Coating L Coating M Component weight (g) weight(g) Weight (g) Resin of 16.2 — — Example 9 Resin of — 14.6 — Example 10515-2¹ — — 25.0 Xylene 83.8 85.4 75.0 Total 100.0  100.0  100.0 

[0132] TABLE P Adhesion Adhesion 1 Hour 1 Day Adhesion Adhesion afterafter Coating 1 Day 7 Day Exposure² Exposure² Example Substrate¹ (0-5)(0-5) (0-5) (0-5) K Bayflex 4 4 4 4 110-35 Sequel 1 2 4 4 1440 Montell 44 4 4 CA186 TSOP-1 3 2 4 4 Himont 5 4 5 5 SD242 L Bayflex 4 4 4 4 110-35Sequel 4 4 4 4 1440 Montell 4 4 4 4 CA186 TSOP-1 4 4 4 4 Himont 5 5 5 4SD242 M Bayflex 0³ 0³ 0³ 0³ 110-35 Sequel 0³ 0³ 0³ 0³ 1440 Montell 0³ 0³0³ 0³ CA186 TSOP-1 0³ 0³ 0³ 0³ Himont 0³ 0³ 0³ 0³ SD242 N Bayflex 4 4 44 110-35 Sequel 4 4 4 4 1440 Montell 4 4 4 4 CA186 TSOP-1 4 4 4 4 Himont5 4 5 4 SD242

[0133] As shown in Table N, there are substantial differences betweenthe copolymers of the present invention and those of U.S. Pat. No.5,955,545, prepared by free-radical polymerization. Because thefree-radical polymerization process results in species that are notgrafted to a chlorinated polyolefin backbone, there are substantialstability problems with the prior art composition. The resin solution ofthe present invention is clear as is a solid film coating prepared fromthe resin solution, even as compared to the CPO precursor. The prior artcomposition is hazy in solution and produces a visibly cloudy solidfilm. This is a clear indicator of the instability of the prior artcomposition and the relative stability of the copolymer of the presentinvention when in solution. Table P indicates the suitability of thecomposition of the present invention, as embodied in Coating K, for usein an adhesion-promoting layer. Although the prior art composition maybe an effective adhesion promoter, its long-term stability and,therefore, its commercial usefulness are questionable in view of thedata presented in Table N.

[0134] The present invention has been described with reference tospecific details of particular embodiments thereof. It is not intendedthat such details be regarded as limitations upon the scope of theinvention except insofar as and to the extent that they are included inthe accompanying claims.

1-42. (canceled)
 43. A copolymer, having a halide content of at leastabout 7.5% by weight, comprising a polyolefin backbone having: (a)pendant halide groups; and (b) pendant homopolymer blocks of two or moredifferent monomers of a radically polymerizable alkenes, at least one ofwhich is attached to tertiary carbons of the halogenated polyolefinbackbone.
 44. The copolymer of claim 43 in which at least one of the twoor more different monomers is an acrylic monomer.
 45. The copolymer ofclaim 44 in which the acrylic monomer contains a group that is reactivewith a curing agent.
 46. The copolymer of claim 45 in which the groupthat is reactive with a curing agent is selected from the groupconsisting of hydroxyl, carboxyl, epoxy, isocyanate and N-methylol. 47.The copolymer of claim 43 in which at least two homopolymer blocks, eachof a different vinyl monomer content, are attached directly to thehalogenated polyolefin backbone.
 48. The copolymer of claim 47 in whichat least one of the blocks is prepared with one or more (meth)acrylicmonomers.
 49. The copolymer of claim 48 in which the (meth)acrylicmonomer-containing block includes one of a hydroxyl group, an epoxygroup, a carboxyl group, an amine group, an alkoxy group, a carbamategroup, an amide group, a urea group and an alkyl ester group.
 50. Thecopolymer of claim 43 in which a first homopolymer block is attacheddirectly to the chlorinated polyolefin backbone and a second homopolymerblock, different from the first block, is attached to an end of thefirst block.
 51. The copolymer of claim 50 in which at least one of theblocks is prepared from one or more (meth)acrylic monomers.
 52. Thecopolymer of claim 51 in which the (meth)acrylic monomer block includesa hydroxyl group.
 53. The copolymer of claim 50 in which the first blockincludes no active hydrogens and the second block includes at least oneactive hydrogen.
 54. The copolymer claim 43 wherein the number averagemolecular weight of the copolymer is from 5,000 to 50,000.
 55. A methodfor producing a copolymer comprising the step of polymerizing one ormore radically polymerizable alkenes in the presence of a halogenatedpolyolefin initiator under controlled radical polymerization conditionsin which the polyolefin initiator includes one or more tertiary halidegroups.
 56. The method of claim 55 in which the halide group is chlorineor bromine.